More than 40 earthquakes occurred in an area below Mauna Loa on Thursday, but the volcano is NOT erupting.
The US Geological Survey’s Hawaiian Volcano Observatory reported that the small swarm of shallow seismicity began at 1am HST Thursday morning. It takes place under the upper seismic zone of Ka’ōiki, under the southeast flank of Mauna Loa and northwest of the summit of Kīlauea. Other data streams from Mauna Loa remain stable and show no signs of increased activity.
COMMENTS
On March 18, 2021, (HVO) recorded more than 40 earthquakes under the upper seismic zone of Ka’ōiki, about 21 miles WNW of the volcano. These earthquakes occur in a cluster about a mile wide and 0.5 to 4 miles below the surface.
The biggest event in the series, late Thursday afternoon, was a magnitude 3.5 earthquake. Most of the events were less than magnitude 2 and not widely reported by residents. Reported felt events were described as weak shaking, with a maximum intensity of II on the modified Mercalli intensity scale.
Clustering shallow earthquakes in this region does not mean an eruption is imminent. HVO has recorded shallow earthquakes in this area for decades during several eruption cycles in both Kīlauea and Mauna Loa. These earthquakes show no signs of magmatic involvement and are part of the volcano’s normal readjustments due to changing tensions within it. Other monitoring data streams for Kīlauea and Mauna Loa, including soil deformation, gas and images, show no signs of increased activity.
HVO continues to closely monitor geological changes, seismicity, deformation and gas emissions from Kīlauea and Mauna Loa volcanoes. HVO will send additional messages and changes to alert levels if justified by changing activity.
For more information on earthquakes in the Ka’ōiki Pali area, see the Volcano Watch article entitled, “Why Are Earthquakes Swarms Happening Around the Ka’ōiki Pali?” published by HVO scientists on March 1, 2012: https://www.usgs.gov/center-news/volcano-watch-why-do-swarms-earthquakes-occur-around-ka-iki-pali.
For information on recent earthquakes in Hawai´i and updates on eruptions, visit the USGS Hawaiian Volcano Observatory website at https://www.usgs.gov/observatories/hawaiian-volcano-observatory.
Mauna Loa activity listings are available by phone: (808) 967-8866. Other Hawaiian Volcano summaries are also available by phone: (808) 967-8877.